Phenyloxyaniline derivatives

ABSTRACT

The present invention relates to phenyloxyaniline derivatives, to methods of their production and to uses thereof.

This application is a divisional of U.S. application Ser. No. 11/896,607filed Sep. 4, 2007 which claims the benefit of the filing date of U.S.provisional Application Ser. No. 60/842,024 filed on Sep. 7, 2006 whichare incorporated herein by reference.

BACKGROUND ART

Peripheral benzodiazepine receptor (PBR) is expressed in most organs andits expression is reported to be increased in activated microglia in thebrain which are the smallest type of glial cells acting as the immunecells of the central nervous system (CNS). Microglia are related toother phagocytic cells including macrophages and dendritic cells.Microglia are thought to be highly mobile cells that play numerousimportant roles in protecting the nervous system. They are also thoughtto play a role in neurodegenerative disorders such as Alzheimer'sdisease, dementia, multiple sclerosis and Amyotrophic lateral sclerosis.Microglia are responsible for producing an inflammatory reaction toinsults (J. Neuroinflammation, 2004, Jul 30; 1(1):14.). The C-11 isotopelabeled version of PK11195 (1) has been widely used for the in vivoimaging of neuroinflamation and PBRs, but its signal in the brain wasnot high enough for stable quantitative analysis.

Furthermore, it has been shown that the development of superiorpositron-emitting ligands, like [¹¹C]DAA1106 (2) (e.g. Eur J. Pharmacol.1999 Apr. 29; 371(2-3):197-204 and Life Sci. 1999; 64(16):1455-64) and[¹⁸F]fluoroethyl-DAA1106 (3) (e.g. J. Nucl. Med., (2006), 47, 43-50),for visualization of PBRs is possible: The compounds 2 and 3 have ahigher binding affinity to PBR and a higher accumulation in the brainthan [¹¹C]PK11195 (1).

The non-radioactive version of compound 2 is claimed by the patentfamily related to WO99/006353, whereas the compound 3 is claimed by thepatent family related to U.S. Pat. No. 6,870,069.

Compound 3 can be synthesized by the alkylation reaction of the phenolDAA1123 (4) with [¹⁸F]-bromo-2-fluoro-ethane (5) as shown in FIG. 6. Thedrawback of the reaction is that the reagent[¹⁸F]-1-bromo-2-fluoro-ethane (5) has to be synthesized fromtrifluoro-methanesulfonsäure-2-bromo-ethyl ester (6) prior phenolalkylation (4→3). Due to the fact that the ¹⁸F isotope has a half-lifeof only 111 min it is a challenge to produce[¹⁸1]-1-bromo-2-fluoro-ethane (5) just in time and to carry out thesubsequent alkylation in good yield. The overall radiochemical yield forthis two-step sequence shown in FIG. 6 is normally lower than 10% yield.

Attempts have been made to synthesize compound 3 directly by startingfrom tosylate 7 (J. Med. Chem., (2004), 2228) by ¹⁸F labeling in aone-step procedure. (see FIG. 7). The reaction was carried out between80° C. and 120° C. However, the radiochemical yields were notreproducible (2%-60%). In addition purification of [¹⁸F]-(3) fromreaction mixture was often difficult since many of the impuritiesresulting from the target and reaction greatly reduced the efficiency(J. Med. Chem., (2004), 2228).

It is known from literature (Biorg. Med. Chem., (2004), 12, 423) thatcompound 7 can be prepared from 4 by alkylation of1,2-bis-tosyloxy-ethane which is commercially available (see FIG. 8).

Compound 4 is prepared from benzyl ether 8 by catalytic hydrogenation(see FIG. 9). Benzyl ether 8 is prepared in a one-pot reaction fromnitro compound 9 and aldehyde 10 (see FIG. 10) Nitro compound 9 issynthesized from difluoride (11) and phenol by nucleophilic aromaticsubstitution reaction. Whereas compound 10 is prepared from phenol 12and benzyl bromide (see FIG. 11) It would be useful to have a practicaland sufficient technique for the synthesis of ¹⁸F-(3) in only one ratherthan in two radiochemical steps. The profile of by-products needs to besimple enough so that the desired product ¹⁸F-(3) can be purifiedeasily. In addition it would be useful to have convenient syntheticroutes to compounds and intermediates which allow the one-step labelingtowards ¹⁸F-(3).

SUMMARY OF INVENTION

The present invention provides novel compounds of Formula I.

The present invention provides novel compounds of Formula II.

The invention further provides a novel process of preparingN-(5-Fluoro-2-phenoxyphenyl)-N-(5-methoxy-2-(2-tosyloxy-ethoxy)-benzyl)acetamide(7) and compounds represented by Formula I or II.

The invention further provides a novel process of preparingN-(5-Fluoro-2-phenoxyphenyl)-N-(2-(2-[¹⁸F]fluoroethoxy)-5-methoxybenzyl)acetamide(3).

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 a: Depicts a HPLC radio-chromatogram 18F fluorination of acompound of the invention.

FIG. 1 b: Depicts aHPLC radio-chromatogram 18F fluorination of acompound of the invention.

FIG. 2 a: Depicts a HPLC radio-chromatogram 18F fluorination of acompound of the invention.

FIG. 2 b: Depicts a HPLC radio-chromatogram 18F fluorination of acompound of the invention.

FIG. 3 a: Depicts a HPLC radio-chromatogram 18F fluorination of acompound of the invention.

FIG. 3 b: Depicts a HPLC radio-chromatogram 18F fluorination of acompound of the invention.

FIG. 4 a: Depicts a HPLC radio-chromatogram 18F fluorination of acompound of the invention.

FIG. 4 b: Depicts a HPLC radio-chromatogram 18F fluorination of acompound of the invention.

FIG. 5 a: Depicts a HPLC radio-chromatogram 18F fluorination of acompound of the invention.

FIG. 5 b: Depicts a HPLC radio-chromatogram 18F fluorination of acompound of the invention.

FIG. 6: Depicts the synthesis of Compound 3 by the alkylation reactionof the phenol DAA1123 (4) with [¹⁸F]-1-bromo-2-fluoro-ethane (5).

FIG. 7: Depicts the synthesis of compound 3 from tosylate 7.

FIG. 8: Depicts the synthesis of compound 7 from compound 4

FIG. 9: Depicts the synthesis of Compound 4 from benzyl ether 8

FIG. 10: Depicts the synthesis of Benzyl ether 8 in a one-pot reactionfrom nitro compound 9 and aldehyde 10.

FIG. 11: Depicts the synthesis of Nitro compound 9 from difluoride (11)and phenol by nucleophilic aromatic substitution reaction and thepreparation of compound 10 from phenol 12 and benzyl bromide.

FIG. 12: Depicts the conversion of compound 13 to compound 3.

FIG. 13: Depicts an example of a synthetic route for forming a compoundof Formula I via a compound of formula II.

FIG. 14: Depicts an example of a synthetic route for forming a compoundof Formula I.

FIG. 15: Depicts an example of a synthetic route for reductivelyN-alkylation forming a compound of Formula I via a compound of formulaIII.

FIG. 16: Depicts a synthetic route for forming a compound of Formula Ivia the reductive N-alkylation of a compound of formula III and analdehyde of formula V.

FIG. 17: Depicts a synthetic route for forming compound 7 via thereductive N-alkylation of a compound of formula III and an aldehyde offormula V.

FIG. 18: Depicts a synthetic route for forming a compound of formula Ifrom a compound of formula II.

FIG. 19: Depicts an example for a synthetic route for forming a compoundof formula I or II by use of a compound of formula V and an electrophileof formula VI and subsequent N-acetylation.

FIG. 20: Depicts an example for the synthetic route for forming acompound of formula I and II by use of a compound of formula VIII and anelectrophile of formula VI.

DETAILED DESCRIPTION OF THE INVENTION

In a first aspect the present invention is directed to compounds offormula I:

wherein

R is

-   -   a) —OS(O)₂-L    -   b) chloro,    -   c) bromo or    -   d) iodo.

In preferred embodiments of compounds of Formula I,

R is

-   -   a) —OS(O)₂-L,    -   b) bromo or    -   c) chloro.

In further preferred embodiments of compounds of Formula I,

R is

-   -   a) —OS(O)₂-L or    -   b) bromo.

L is

-   -   a) branched or unbranched alkyl    -   b) perhalo alkyl    -   c) aralkyl    -   d) alkyl-phenyl    -   e) (di-alkyl)-phenyl    -   f) (tri-alkyl)-phenyl    -   g) (alkoxy-phenyl)    -   h) (nitro-phenyl)    -   i) (halo-phenyl)    -   j) naphtyl or    -   k) heteroaryl        whereas L is not (para-methyl)-phenyl.

In preferred embodiments of compounds of Formula I, L is

-   -   a) methyl    -   b) trifluormethyl    -   b) nonafluorobutyl    -   c) (nitro-phenyl)    -   d) (halo-phenyl)    -   e) C₁-C₆ alkylphenyl or    -   f) (2,4,6-C₁-C₆ trialkyl)phenyl        whereas L is not (para-methyl)-phenyl.

In further preferred embodiments of compounds of Formula I,

L is

-   -   a) methyl    -   b) trifluoimethyl or    -   c) nonafluorobutyl

A preferred series of compounds of Formula I include mesyloxy and bromoderivatives having the following structures:

In a second aspect the present invention is directed to compounds offormula II which are possible starting materials of compounds of formulaI:

wherein

A is

-   -   a) hydrogen    -   b) SiR¹ ₃    -   c) CH₂-G    -   d) C(O)-Q    -   e) C(O)O-E    -   f) —(R²-phenyl)    -   g) —((R²)-2-phenyl)    -   h) tetrahydropyranyl    -   i) (1-alkoxy)-alkyl    -   j) (1-alkoxy)-cycloalkyl    -   k) allyl or    -   l) tert-butyl.

In preferred embodiments of compounds of Formula II

A is

-   -   a) hydrogen    -   b) SiR¹ ₃    -   c) CH₂-G    -   d) tetrahydropyranyl    -   e) allyl or    -   f) tert-butyl.

In further preferred embodiments of compounds of Formula II,

A is

-   -   a) hydrogen    -   b) SiR¹ ₃    -   c)CH₂-G    -   d) tetrahydropyranyl or    -   e) tert-butyl.

G is

-   -   a) phenyl    -   b) alkoxy    -   c) dimethoxyphenyl    -   d) nitrophenyl    -   e) halophenyl    -   f) di-halophenyl    -   g) cyanophenyl    -   h) p-biphenyl    -   i) acylaminophenyl    -   j) triphenyl    -   k) (methoxyphenyl)phenyl    -   l) di(methoxyphenyl)phenyl    -   m) α-naphtyldiphenyl or    -   n) hydrogen

In preferred embodiments of compounds of Formula II,

G is

-   -   a) phenyl    -   b) methoxy    -   c) p-methoxyphenyl    -   d) p-nitrophenyl    -   e) p-chlorophenyl or    -   f) triphenyl.

In further preferred embodiments of compounds of Formula II

G is

-   -   a) phenyl    -   b) methoxy or    -   c) p-methoxyphenyl.

Q is

-   -   a) hydrogen    -   b) C₁-C₅ branched or unbranched alkyl    -   c) halomethyl    -   d) dihalomethyl    -   e) trihalomethyl    -   f) phenyl    -   g) biphenyl    -   h) triphenylmethoxymethyl or    -   i) phenoxymethyl.

In preferred embodiments of compounds of Formula II

Q is

-   -   a) hydrogen    -   b) methyl    -   c) phenyl or    -   d) phenoxymethyl.

In further preferred embodiments of compounds of Formula II,

Q is

-   -   a) is methyl    -   b) phenyl.

E is

-   -   a) lower branched or unbranched alkyl    -   b) methoxymethyl    -   c) vinyl    -   d) allyl    -   e) benzyl    -   f) methoxyphenyl    -   g) dimethoxyphenyl or    -   h) nitrophenyl

In preferred embodiments of compounds of Formula II,

E is

-   -   a) methyl    -   b) tert-butyl    -   c) methoxymethyl or    -   d) phenyl

In further preferred embodiments of compounds of Formula II,

E is

-   -   a) methyl    -   c) tert-butyl    -   b) phenyl

R¹ is independently from each other

-   -   a) lower branched or unbranched alkyl    -   b) phenyl or    -   c) benzyl and

In preferred embodiments of compounds of Formula II,

R¹ is independently from each other

-   -   a) methyl    -   b) ethyl    -   c) isopropyl    -   d) tert-butyl    -   e) phenyl or    -   f) benzyl

In further preferred embodiments of compounds of Formula II,

R¹ is independently from each other

-   -   a) methyl    -   b) ethyl    -   c) isopropyl    -   d) tert-butyl or    -   e) phenyl

R² is independently from each other

-   -   a) methoxy    -   b) nitro    -   c) halo or    -   d) cyano

In preferred embodiments of compounds of Formula II,

R² is independently from each other

-   -   a) methoxy    -   b) nitro    -   c) chloro

In further preferred embodiments of compounds of Formula II,

R² is independently from each other

-   -   a) methoxy    -   b) nitro

A preferred series of compounds of Formula II include derivatives havingthe following structures:

As used in the specification and appended claims unless specified to thecontrary, the term “lower un-branched or branched alkyl” shall have thefollowing meaning: a substituted or unsubstituted, straight or branchedchain monovalent or divalent radical consisting substantially of carbonand hydrogen, containing no unsaturation and having from one to eightcarbon atoms, e.g. but not limited to methyl, ethyl, n-propyl, n-pentyl,1,1-dimethylethyl (t-butyl), n-heptyl, and the like.

The term “aryl” as employed herein by itself or as part of another grouprefers to monocyclic or bicyclic aromatic groups containing from 6 to 12carbons in the ring portion, preferably 6-10 carbons in the ringportion, such as phenyl, naphthyl or tetrahydronaphthyl. The term“heteroaryl” as employed herein refers to groups having 5 to 14 ringatoms; 6, 10 or 14 Π (pi) electrons shared in a cyclic array; andcontaining carbon atoms and 1, 2, 3 or 4 oxygen, nitrogen or sulfurheteroatoms (where examples of heteroaryl groups are: thienyl,benzo[b]thienyl, naphtho[2,3-b]thienyl, thianthrenyl, furyl, pyranyl,isobenzofuranyl, benzoxazolyl, chromenyl, xanthenyl, phenoxathiinyl,pyrrolyl, imidazolyl, pyrazolyl, pyridyl, pyrazinyl, pyrimidinyl,pyridazinyl, indolizinyl, isoindolyl, 3H-indolyl, indolyl, indazolyl,purinyl, 4H-quinolizinyl, isoquinolyl, quinolyl, phthalazinyl,naphthyridinyl, quinazolinyl, cinnolinyl, pteridinyl, 4aH-carbazolyl,carbazolyl, carbolinyl, phenanthridinyl, acridinyl, perimidinyl,phenanthrolinyl, phenazinyl, isothiazolyl, phenothiazinyl, isoxazolyl,furazanyl and phenoxazinyl groups).

If a chiral center or another form of an isomeric center is present in acompound according to Formula I or II of the present invention, allfoul's of such isomer, including enantiomers and diastereoisomers, areintended to be covered herein. Compounds containing a chiral center maybe used as racemic mixture or as an enantiomerically enriched mixture orthe racemic mixture may be separated using well-known techniques and anindividual enantiomer maybe used alone. In cases in which compounds haveunsaturated carbon-carbon bonds double bonds, both the cis-isomer andtrans-isomers are within the scope of this invention. In cases whereincompounds may exist in tautomeric forms, such as keto-enol tautomers,each tautomeric form is contemplated as being included within thisinvention whether existing in equilibrium or predominantly in one form.

In a third aspect the present invention is directed to a process forpreparingN-(5-Fluoro-2-phenoxyphenyl)-N-(5-methoxy-2-tosyloxyethoxybenzyl)acetamide(7) or a compound represented by Formula I or II characterized by

a) reductively N-alkylating a compound of formula III:

with an aldehyde of formula IV

and subsequent N-acetylation,b) N-alkylating an aniline of formula V:

with an electrophile of formula VI

and subsequent N-acetylation,c) alkylation of phenol 4 with an

electrophile of formula VII

d) N-alkylating of the compound of formula VIII

with an electrophile of formula VI.wherein

X is a) nitro or

-   -   b) amino and

Z is

-   -   a) R    -   b) tosyloxy or    -   c) O-A and        whereas R and A are above-defined.

In preferred embodiments of compounds of formula VII,

Z is

-   -   a) methanesulphonyloxy    -   b) trifluoromethansulphonyloxy    -   c) nonafluorobutanesulfonyloxy    -   d) tosyloxy    -   e) bromo    -   f) O-A        whereas A is above-defined.

In further preferred embodiments of compounds of formula VII,

Z is

-   -   a) methanesulphonyloxy    -   b) trifluoromethansulphonyloxy    -   c) nonafluorobutanesulfonyloxy    -   d) tosyloxy    -   e) bromo    -   f) hydroxyl    -   g) (tert-butyl dimethyl) silyloxy    -   h) (triisopropyl) silyloxy    -   i) phenyl    -   j) tetrahydropyranyl or    -   k) tert-butyl.

In further preferred embodiments of compounds of formula VII,

Z is

-   -   a) methanesulphonyloxy    -   b) trifluoromethansulphonyloxy    -   c) nonafluorobutanesulfonyloxy    -   d) tosyloxy    -   e) bromo    -   f) hydroxyl    -   g) (tert-butyl dimethyl)silyloxy    -   h) (triisopropyl)silyloxy    -   ii) phenyl-methyl)oxy    -   jj) (2-tetrahydropyranyl)oxy 1, or    -   kk) tert-butyloxy.

R³ is

-   -   a) R or    -   b) tosyloxy        whereas R is above-defined.

In preferred embodiments of compounds of formula V¹,

R³ is

-   -   a) R        whereas R is above-defined.

The above mentioned processes of forming compound 7 or a compound offormula I and II avoid the laborious protecting group strategy as it isshown in FIGS. 9 and 11 and as it was reported e.g. in Biorg. Med.Chem., (2004), 12, 423. In this mentioned publication the phenolprotecting “benzyl” has to be installed and deprotected within arelatively short sequence. The third aspect of the present inventionprovides a more convergent approach to synthesize a suited precursor forthe later radiofluorination reaction.

A forth aspect of the invention is directed to a process of preparingcompound 3 which is characterized by the nucleophilic ¹⁸Fradiofluorination of compound 7 or a compound of formula I in only oneradiochemical step. In contrast to the published one-step ¹⁸F labellingprocedure (J. Med. Chem., (2004), 2228) the forth aspect of the presentinvention provides additional starting materials and/or new parameterswhich allow the ¹⁸F fluorination towardsN-(5-Fluoro-2-phenoxyphenyl)-N-(2-(2-[¹⁸F]fluoroethoxy)-5-methoxybenzyl)acetamide(3) without generating a disadvantageous amount of by-products which arecostly or difficult to separate. The present invention comprises anapproach for the nucleophilic ¹⁸F radiofluorination towardsN-(5-Fluoro-2-phenoxyphenyl)-N-(2-(2-[¹⁸F]fluoroethoxy)-5-methoxybenzyl)acetamide(3) which is characterized by use of starting materials represented by

a) compound 7 and ¹⁸F anions which are reacted at temperatures in therange of from 121° C.-160° C. and, optionally, subsequent use of acid,orb) compounds of formula I and ¹⁸F anions which are reactedat temperatures in the range of from 50° C. to 160° C.

In preferred embodiments of ¹⁸F radiofluorinations towardsN-(5-Fluoro-2-phenoxyphenyl)-N-(2-(2-[¹⁸F]fluoroethoxy)-5-methoxybenzyl)acetamide(3) the reaction is characterized by use of starting materialsrepresented by

a) compound 7 and ¹⁸F anions which are reacted at temperatures in therange of from 121° C. to 150° C. and, optionally, subsequent use ofmineral acids with concentrations between 0.5 N-6 N, orb) compounds of formula I and ¹⁸F anions which are reacted attemperatures in the range of from 75° C. to 150° C.

In further preferred embodiments of ¹⁸F radiofluorinations towardsN-(5-Fluoro-2-phenoxyphenyl)-N-(2-(2-[¹⁸F]fluoroethoxy)-5-methoxybenzyl)acetamide(3) the reaction is characterized by use of starting materialsrepresented by

a) compound 7 and ¹⁸F anions which are reacted at temperatures in therange of from 121° C. to 140° C., and, optionally, subsequent use ofmineral acids with concentrations between 2 N-6 N, orb) compounds of formula I and ¹⁸F anions which are reacted attemperatures in the range of from 85° C. to 140° C.

The objects of the present invention are also solved by a process ofpreparing compound 3

characterized bya) reacting compound 7

with ¹⁸F anions,at temperatures in the range of from 121° C. to 160° C., and,optionally, upon obtainment of compound 3, addition of acid,orb) reacting a compound of formula I, as defined in any of claims 1-6with ¹⁸F anions at temperatures in the range of from 50° C. to 160° C.

In one embodiment,

a) compound 7 is reacted with ¹⁸F anions at temperatures in the range offrom 121° C. to 150° C., and, optionally, upon obtainment of compound 3,at least one mineral acid having a concentration in the range of from0.5N-6N is added,orb) a compound of formula I is reacted with ¹⁸F anions at temperatures inthe range of from 75° C. to 150° C.

Preferably,

a) compound 7 is reacted with ¹⁸F anions, at temperatures in the rangeof from 121° C. to 140° C. and, optionally, upon obtainment of compound3, at least one mineral acid having a concentration in the range of from2N-6N is added,orb) a compound of formula I is reacted with ¹⁸F anions at temperatures inthe range of from 85° C. to 140° C.

In one embodiment in each of the reactions a) and b), the reaction with¹⁸F anions is conducted over a period in the range of from 1 to 60minutes, preferably 5 to 50 minutes, more preferably 10 to 40 minutes.

The objects of the present invention are also solved by a compositioncomprising a compound according to Formula I, preferably as defined inany of claims 1-6, and a pharmaceutically acceptable carrier or diluent.

The objects of the present invention are furthermore solved by a kitcomprising a sealed vial containing a compound according to Formula I,preferably as defined in any of claims 1-6, wherein, more preferably,said sealed vial contains a predetermined quantity of said compound.

The objects of the present invention are furthermore solved by acompound according to formula I, as defined in any of claims 1-6, foruse as a pharmaceutical.

The objects of the present invention are furthermore solved by a use ofa compound according to formula I, as defined in any of claims 1-6, forthe manufacturing of a diagnostic imaging agent, wherein, preferably,said diagnostic imaging agent is for imaging diseases of the centralnervous system.

The term “acid” as employed herein refers to mineral acids, includingbut not limited to acids such as hydrochloric, hydrobromic, hydroiodic,perchloric, phosphoric, carbonic, nitric or sulphuric acid or toappropriate organic acids which includes but not limited to acids suchas aliphatic, cycloaliphatic, aromatic, araliphatic, heterocyclic,carboxylic and sulphonic acids, examples of which are formic, acetic,trifluoracetic, propionic, succinic, glycolic, gluconic, lactic, malic,fumaric, pyruvic, benzoic, anthranilic, mesylic, fumaric, salicylic,phenylacetic, mandelic, embonic, methansulfonic, ethanesulfonic,benzenesulfonic, phantothenic, toluenesulfonic and sulfanilic acid.

If, in the context of the process of preparing compound 3, the term “atleast one mineral acid having a concentration in the range of form 0.5N-6N” is used, this is meant to refer to a scenario, wherein the atleast one mineral acid has a concentration in the indicated range.However, this term should also be understood as encompassing a scenariowherein more than one mineral acid is used, e.g. a mixture of severalmineral acids, and the total acid concentration, i.e. the sum of allindividual mineral acid concentrations is in the indicated range of from0.5 N-6N.

The provision of ¹⁸F anions is known to someone skilled in the art andin one embodiment is achieved by providing aqueous H¹⁸F to which a base,for example in the form of potassium carbonate or tetra alkyl ammoniumcarbonate is added. The aqueous H¹⁸F may be obtained from a synchrotron.

It is important that a radiofluorination causes as little by-products aspossible in order to avoid a difficult purification of the desiredproduct.

As depicted in FIG. 12 a compound of formula I, e.g. compound 13, can beradio-fluorinated to obtain the desired product 3 (see FIG. 1 a). Thereaction causes less non-radioactive by-products (see FIG. 1 b) comparedto a reaction in which compound 7 is converted to 3 at any temperature(compare FIG. 2 b with 3 b and 4 b as example). Compound 7 as startingmaterial shows surprisingly also an improved profile of by-productsregarding radiofluorination by treatment with ¹⁸F anion if thetemperature is above 120° C. (compare FIG. 2 b with 4 b). If onecompares the nucleophilic radiofluorination reaction of a compound offormula I with compound 7 it is obvious that radiofluorinations ofcompounds of formula I can be conducted at all temperatures (see e.g.FIGS. 5 a and 5 b). The radiofluorination reaction can be carried out,for example in a typical reaction vessel (e.g. Wheaton vial) which isknown to someone skilled in the art, or in a microreactor. The reactioncan be heated by typical methods, e.g. oil bath, heating block ormicrowave. Furthermore it can be useful to add acid to the crude productor to the reaction mixture after the radiofluorinations of compound 7 orof compounds of formula I towards compound 3 has been carried out. Thetreatment with acid can lead surprisingly to an improved profile ofby-products.

The radiofluorination reactions are carried out in dimethylformamidewith potassium carbonate as base and “kryptofix” as crown-ether. Butalso other solvents can be used which are well known to experts. Thesepossible conditions include, but are not limited to: dimethylsulfoxidand acetonitril as solvent and tetraalkyl ammonium and tertraalkylphosphonium carbonate as base. Water and/or alcohol can be involved insuch a reaction as co-solvent. The radiofluorination reactions areconducted for one to 60 minutes. Preferred reaction times are five to 50minutes. Further preferred reaction times are 10 to 40 min.

FIG. 13 depicts an example of a synthetic route for forming a compoundof formula I via a compound of formula II:

Compound 4 (J. Med. Chem.; 47; 9; (2004); 2228-2235) can be alkylated byuse of e.g. benzyl protected bromoethanol (Bioorg. Med. Chem. Lett.; 15;22; (2005); 4989-4993), potassium carbonate and sodium iodide indimethylformamide to obtain ether 15. But also other bases, includingbut not limited to caesium or sodium carbonate, sodium hydroxid,potassium hydroxid, lithium hydroxid, tetra-alkyl hydroxid, sodiumhydrid and other solvents, including but not limited to acetone,tetrahydrofuran, eventually mixed with water, are possible. Compound 15is deprotected by heterogeneous catalysis and hydrogen. Suited reactionconditions are e.g. palladium on carbon and isopropanol. Other possiblereagents and solvents for this kind of reaction of deprotection areknown to experts and listed in T. Greene, “Protective Groups in OrganicSynthesis”, Wiley & Sons, 1999. The resulting alcohol 13 is thenconverted to compound 16 by use of e.g. mesylchloride, triethylamin anddichloromethane. Other possible solvents and bases including but notlimited to, are dichloroethane, ethers, ethyl acetate, diisopropyl ethylamine, DABCO ect.

FIG. 14 depicts another example of a synthetic route for forming acompound of Formula I. Phenol 4 can be alkylated by use of1,2-bis-methanesulfonyloxy-ethane (J. Med. Chem.; 47; 17; (2004);4300-4315), potassium carbonate and sodium iodide in dimethylformamideto obtain mesylate 13. But also other bases, including but not limitedto caesium or sodium carbonate, sodium hydroxid, potassium hydroxid,lithium hydroxid, tetraalkyl hydroxid, sodium hydrid and other solvents,including but not limited to acetone, tetrahydrofuran, eventually mixedwith water, are possible.

FIG. 15 depicts another example of a synthetic route for reductivelyN-alkylation forming a compound of Formula I via a compound of formulaIII:

Nitro-compound 9 is reduced to the corresponding aniline 18. A possiblereducing agent for this reaction is hydrogen with palladium on carbon.Aniline 18 is converted in a reductive amination reaction withtris-acetoxy sodium borohydrid in dichloromethane and aldehyde 21 andsubsequent acetylation with acetic acid anhydride to obtain theacetylated secondary aniline 22. Other useful reducing agents arewell-known to experts: e.g. sodium cyano borohydrid in methanol orhydrogen and heterogenous catalysts (e.g. palladium on carbon (Bioorg.Med. Chem. Lett.; 15; 22; 2005; 4989-4993) or platinum oxide), dibutyltin chloride and phenyl silane (Org. Lett.; 25; 2005; 5653-5656).Deprotection of the tetrahydropyranyl ether 22 under acidic conditionswith tosyl acid in methanol resulted in alcohol 16. The subsequentmesylation towards compound 13 has already been described in FIG. 13.

FIG. 16 depicts another synthetic route for forming a compound ofFormula I via the reductive N-alkylation of a compound of formula IIIand an aldehyde of formula V. Aniline 18 (comp. formula V) can beconverted in a reductive amination reaction with tris-acetoxy sodiumborohydrid and acetic acid in dichloromethane and aldehyde 23 andsubsequent acetylation, e.g. with acetic acid anhydride, to obtain theacetylated secondary aniline 13. Other useful reducing agents arewell-known to experts: e.g. sodium cyano borohydrid in methanol orhydrogen and heterogenous catalysts (e.g. palladium on carbon (Bioorg.Med. Chem. Lett.; 15; 22; (2005); 4989-4993) or platinum oxide), dibutyltin chloride and phenyl silane (Org. Lett.; 25; (2005); 5653-5656).Aldehyde 23 is prepared in an alkylation reaction with commerciallyavailable phenol 19 and 1,2-bis-methanesulfonyloxy-ethane (J. Med.Chem.; 47; 17; (2004); 4300-4315) by use of potassium carbonate and indimethylformamide. But also other bases, including but not limited tocaesium or sodium carbonate, sodium hydroxid, potassium hydroxid,lithium hydroxid, tetraalkyl hydroxid, sodium hydrid and other solvents,including but not limited to acetone, tetrahydrofuran, eventually mixedwith water, are possible.

FIG. 17 depicts a very similar synthetic route for forming compound 7via the reductive N-alkylation of a compound of formula III and analdehyde of formula V.

FIG. 18 depicts another synthetic route for forming a compound offormula I from a compound of formula II whereas bromide 25 is suited asprecursor (starting material) for the nucleophilic ¹⁸F-radiofluorinationreaction towards compound 3.

Alcohol 16 is converted to the corresponding bromide 25 by methods whichare well known to experts. For example alcohol 16 is treated withtriphenylphosphin and tetrabromomethane in dichloromethane to obtainbromide 25.

FIG. 19 depicts an example for a synthetic route for forming a compoundof formula I or II by use of a compound of formula V and an electrophileof formula VI and subsequent N-acetylation.

Aniline 18 is alkylated by bis-mesylate 24. The alkylation is highlyselective due to the more activated benzylic leaving group. SubsequentN-acetylation with acetic acid anhydride or by other acetylating agentswhich are well-known to experts resulted in compound 13. Bis-mesylate 24is the product of the mesylation reaction of his-alcohol 26 by typicalmethods which are well-known to experts. Bis-alcohol (26) can beprepared from phenol 25 (Rarechem) with 2-chloro-ethanol or another2-substituted ethanol derivative with a leaving group in 2-position(e.g. 2-bromo-ethanol; comp. Farmaco Ed. Sci.; 14; (1959); 159, 170 andTetrahedron; 59; 29; 2003; 5457-5468).

FIG. 20 depicts an example for the synthetic route for forming acompound of formula and II by use of a compound of formula VIII and anelectrophile of formula VI. Compound 18 is acetylated by standardmethods using acetanhydride and pyridine. The phenol functionality ofcompound 25 is alkylated with bromide 28 (J. Med. Chem.; 47; 25; 2004;6124-6127) using caesium carbonate as base and DMF as solvent. But alsoother base/solvent combinations are possible including, but not limitedto potassium carbonate, sodium carbonate, sodium hydride,tetrahydrofuran and acetonitril. The benzylic alcohol 29 is brominatedin an “Appel reaction” to compound 30 with tetra-bromo methane andtriphenylphosphine in tetrahydrofuran. Amide 27 is deprotonated withsodium hydride in TIIF and substituted with bromide 30 to obtaincompound 31. The silyl ether 31 can be deprotected towards compound 16(FIG. 13) using either acid or fluoride anions in e.g. tetrahydrofuran(e.g. analogous to J. Am. Chem. Soc.; 128; 13; 2006; 4356-4364.)”

Experimental Part

“General procedure A (alkylation of phenol derivatives with O-protected2-bromo ethanols):

To a solution of phenol derivative (30 mmol) in 60 ml dry DMF was added35 mmol caesium carbonate at 0° C. The reaction mixture was stirred for30 min. 35 mmol O-protected 2-bromo-ethanol is dissolved in 10 ml DMF isadded dropwisly. The reaction mixture is stirred for 10-16 hours at roomtemperature. The solvent is evaporated and the residue is diluted withethyl acetate and water. The organic phase is separated. The aqueousphase is extracted three times with ethyl acetate. The combined organicphases were washed with brine, dried with magnesium sulphate and wereevaporated. The residue was purified by silica chromatography usingethylacetate/hexane solvent mixtures as gradient.

General procedure B (Appel reaction of benzylic alcohol derivativestowards corresponding bromides):

To a cooled 0° C. solution of benzylic alcohol derivative (20 mmol),PPh₃ (30 mmol), and CH₂Cl₂ (500 mL) was added CBr₄ (30 mmol)portionwise. The ice bath was removed and the solution stirredovernight. Silica gel was added to the mixture and the solvent removedin vacuo. Flash chromatography (EtOAc/hexanes) afforded the benzylbromide derivative.

General procedure C (Alkylation ofN-(5-Fluoro-2-phenoxy-phenyl)-acetamide):

To a suspension of 12 mmol sodium hydride in 20 ml dry THF 10 mmolN-(5-Fluoro-2-phenoxy-phenyl)-acetamide which is dissolved in 5 ml dryTHF and were added dropwisely at 0° C. The reaction mixture was stirredfor 30 min at room temperature. 12 mmol bromide were dissolved in 5 mldry tetrahydrofuran and were added to the reaction mixture dropwisely at0° C. The reaction mixture was refluxed for 4 hours. The mixture iscooled to room temperature and poured onto a vigorously stirred diethylether-water mixture. The organic phase is separated. The aqueous phaseis extracted three times with ethyl acetate. The combined organic phasesare washed with brine, dried with magnesium sulphate and are evaporated.The residue is purified by silica chromatography using ethylacetate/hexane solvent mixtures as gradient.

General procedure D (acidic deprotection of acid sensitive hydroxylprotecting groups):

To a solution of 3 mmol hydroxyl-protected compound in 5 ml dioxane isadded 3 ml of a 4N HCl solution in dioxane (Aldrich) dropwisly at 0° C.The reaction mixture is stirred at 40° C. for 6 hours. Diethyl ether andsaturated sodium hydrogen carbonate solution is added at 0° C. Thetwo-phase mixture is stirred vigorously for 20 min. The organic phase isseparated. The aqueous phase is extracted three times with ethylacetate. The combined organic phases are washed with brine, dried withmagnesium sulphate and are evaporated. The residue is purified by silicachromatography using ethyl acetate/hexane solvent mixtures as gradient.

Example 1 a) Synthesis of5-Methoxy-2-[2-(tetrahydropyran-2-yloxy)-ethoxy]-benzaldehyde (1a)

To a vigorously stirred solution of 15.2 g (100 mmol)2-hydroxy-5-methoxy-benzaldehyde and 42.4 g (130 mmol) caesium carbonatein 350 ml DMF at 0° C. was added 26.1 g (125 mmol)2-(2-Bromo-ethoxy)-tetrahydro-pyran (J. Org. Chem.; 50; 22; (1985);4238-4245) in 50 ml DMF dropwisely. The reaction mixture was stirredvigorously at 70° C. for 6 h. The solvent was evaporated. 200 ml waterand 200 ml ethyl acetate were added. The organic phase was separated.The aqueous phase was extracted three times with 100 ml ethyl acetateeach. The combined organic phases were washed with 50 ml water and 50 mlbrine. The organic phase was dried with magnesium sulphate andevaporated. The crude product was purified by silica columnchromatography (ethylacetate:hexane 1:3). The desired product 1a wasobtained in 81% yield (22.7 g, 81 mmol) as yellow oil.

MS-ESI: 281 (M⁺ + 1, 100). Elementary analysis: C 64.27% H 5.34%Determined: C 64.25% H 5.35%

b) Synthesis of 5-fluoro-2-phenoxy-phenylamine (1b)

The atmosphere over a stirred solution of 11.6 g (50 mmol)4-fluoro-2-nitro-1-phenoxy-benzene and catalytic amount of palladium oncarbon in 150 ml iso-propanol at 20° C. was saturated with hydrogen. Thereaction mixture was stirred vigorously at 25° C. for 8 h. The reactionmixture was filtered over celite. The filtrate was evaporated. 200 mlwater and 200 ml dichloromethane were added. The organic phase wasseparated. The aqueous phase was extracted three times with 100 mldichloromethane each. The combined organic phases were washed with 50 mlwater and 50 ml brine. The organic phase was dried with magnesiumsulfate and evaporated. The crude product 1b was used withoutpurification. The desired crude product 1b was obtained in 94% yield(9.54 g, 47 mmol) as yellow oil.

MS-ESI: 204 (M⁺ + 1, 100). Elementary C 70.93% H 4.96% F 9.35% N 6.89%analysis: Determined: C 71.00% H 4.92% F 9.33% N 6.87%

c) Synthesis of(5-Fluoro-2-phenoxy-phenyl)-{5-methoxy-2-[2-(tetrahydro-pyran-2-yloxy)-ethoxy]-benzyl}-amine(1c)

To stirred solution of 9.1 g (45 mmol) 1b, 12.6 g (45 mmol) 1a and onedrop of glacial acid in 60 ml dichloroethane (pH=5) were added 14.8 g(70 mmol) sodium tris-acetoxy hydro borane. The reaction mixture wasstirred over night and diluted with 5 ml water. The pH value wasadjusted with aqueous sodium hydroxyd solution to pH=8-9. The mixturewas extracted three times with dichloromethane. The combined organicphases were washed with water and brine and were dried with magnesiumsulfate. The desired crude product 1c was obtained in 66% yield (13.9 g,29.7 mmol) as yellow oil. The crude product 1c was used without furtherpurification.

MS-ESI: 468 (M⁺+1, 89).

d) Synthesis ofN-(5-Fluoro-2-phenoxy-phenyl)-N-{5-methoxy-2-[2-(tetrahydro-pyran-2-yl-oxy)-ethoxy]-benzyl}-acetamide(1d)

To a solution of 5.0 g (10.7 mmol) crude 1c in 50 ml ml pyridine wasadded 4.37 g (42.8 mmol) acetic acid anhydride. The reaction mixture wasstirred over night and poured into ice-cold ethyl acetate. The organicphase was washed with water and brine and were dried with magnesiumsulfate. The crude product was purified by silica column chromatography(ethyl acetate:hexane gradient 1:8→1:4). The desired product 1d wasobtained in 84% yield (4.5 g, 8.9 mmol).

MS-ESI: 510 (M⁺ + 1, 100). Elementary C 68.36% H 6.33% F 3.73% N 2.75%analysis: Determined: C 68.34% H 6.34% F 3.71% N 2.74%

e) Synthesis ofN-(5-Fluoro-2-phenoxy-phenyl)-N-[2-(2-hydroxy-ethoxy)-5-methoxy-benzyl]-acetamide(1e)

To a solution of 1.53 g (3.0 mmol) 1d in 15 ml methanol was added acatalytic amount of tosyl acid. The reaction mixture was stirred for 4 hat 25° C. The reaction mixture was poured in ice-cold ethyl acetate. Thesolution was washed twice with ice-cold diluted aqueous sodium hydrogencarbonate solution and brine and dried with magnesium sulfate. The crudeproduct was purified by silica column chromatography (ethylacetate:hexane gradient 1:4→1:2). The desired product 1e was obtained in71% yield (0.91 g, 2.13 mmol) as yellow oil.

MS-ESI: 426 (M⁺ + 1, 100). Elementary C 67.75% H 5.69% F 4.47% N 3.29%analysis: Determined: C 67.72% H 5.71% F 4.46% N 3.28%

f) Synthesis ofN-(5-Fluoro-2-phenoxy-phenyl)-N-[2-(2-mesyloxy-ethoxy)-5-methoxy-benzyl]-acetamide(1f)

To a solution of 300 mg (0.71 mmol) 1e and 139 mg (1.06 mmol)diisopropyl ethyl amine in 5 ml dichloromethane was added 97 mg (0.85mmol) mesyl chloride in 0.5 ml dichloromethane drop wisely at −10° C.The stirred reaction mixture was warmed over a period of 4 h to roomtemperature and diluted with dichloromethane. The organic phase waswashed with saturated sodium hydrogen carbonate solution, water andbrine. The organic phase was dried with magnesium sulfate. The crudeproduct was purified by silica column chromatography (ethylacetate:hexane gradient 1:6→1:2). The desired product 1f was obtained in88% yield (346 mg, 0.62 mmol) as yellow oil.

MS-ESI 559 (M⁺ + 1, 60). Elementary C 59.63% H 5.20% F 3.77% N 2.78%analysis: Determined: C 59.62% H 5.20% F 3.78% N 2.77%

g) Synthesis ofN-(5-Fluoro-2-phenoxyphenyl)-N-(2-(2-[¹⁸F]fluoro-ethoxy)-5-methoxybenzyl)acetamide(1g)

To a Wheaton vial (5 ml) charged with 2.5 mg Kryptofix 222 in 0.75 mlacetonitrile and 0.5 mg potassium carbonate and the fluorine containingwater (2.2 GBq, 250 μl) was added. The solvent was removed by heating at120° C. for 10 rains under a stream of nitrogen. Anhydrous MeCN (1 ml)is added and evaporated as before. This step is repeated again. Asolution of 1 g (2 mg) in 0.705 ml anhydrous DMF is added. After heatingat 130° C. for 30 min. The crude reaction mixture is analyzed using ananalytical HPLC: ACE3-C18 50 mm*4.6 mm; solvent: 5% acetonitril-95%acetonitril in water in 7 min., flow: 2 ml/min. The F-18 labeled product1g is confirmed by co-injection with the non-radioactive F-19 fluorostandard on the analytical HPLC. The crude product (160 MBq) waspurified by preparative HPLC column: ACES-C18-HL 250 mm*10 mm; solvent62% acetonitril-38% water, isocratic 20 min., flow: 3 ml/min. Thedesired product 1g was obtained (45 MBq) as reconfirmed by co-injectionwith the non-radioactive F-19 fluoro standard on the analytical HPLC.

Example 2 a) Synthesis of 2-(2-Benzyloxy-ethoxy)-5-methoxy-benzaldehyde(2a)

To a vigorously stirred solution of 15.2 g (100 mmol)2-hydroxy-5-methoxy-benzaldehyde and 42.4 g (130 mmol) caesium carbonatein 350 ml DMF at 0° C. was added 26.9 g (125 mmol)(2-Bromo-ethoxymethyl)-benzene (Adrich) in 50 ml DMF dropwisely. Thereaction mixture was stirred vigorously at 70° C. for 6 h. The solventwas evaporated. 200 ml water and 200 ml ethyl acetate were added. Theorganic phase was separated. The aqueous phase was extracted three timeswith 100 ml ethyl acetate each. The combined organic phases were washedwith 50 ml water and 50 ml brine. The organic phase was dried withmagnesium sulphate and evaporated. The crude product was purified bysilica column chromatography (gradient ethylacetate:hexane 1:3→1:2). Thedesired product 2a was obtained in 86% yield (24.6 g, 86 mmol) as yellowoil.

MS-ESI: 287 (M⁺ + 1, 100). Elementary analysis: C 71.31% H 6.34%Determined: C 71.29% H 6.35%

b) Synthesis of[2-(2-benzyloxy-ethoxy)-5-methoxy-benzyl]-(5-fluoro-2-phenoxy-phenyl)-amine(2b)

To stirred solution of 4.6 g (23 mmol) 1b, 6.3 g (23 mmol) 2a and onedrop of glacial acid in 35 ml dichloroethane (pH=5) were added 7.4 g (35mmol) sodium tris-acetoxy hydro borane. The reaction mixture was stirredover night and diluted with 3 ml water. The pH value was adjusted withaqueous sodium hydroxyd solution to pH=8-9. The mixture was extractedthree times with dichloromethane. The combined organic phases werewashed with water and brine and were dried with magnesium sulfate. Thedesired crude product 2b was obtained in 78% yield (8.5 g, 17.9 mmol) asyellow oil. The crude product 2b was used without further purification.

MS-ESI: 475 (M⁺+1, 81).

c) Synthesis ofN-[2-(2-benzyloxy-ethoxy)-5-methoxy-benzyl]-N-(5-fluoro-2-phenoxy-phenyl)-acetamide(2c)

To a solution of 5.08 g (10.7 mmol) crude 2b in 50 ml ml pyridine wasadded 4.37 g (42.8 mmol) acetic acid anhydride. The reaction mixture wasstirred over night and poured into ice-cold ethyl acetate. The organicphase was washed with water, diluted aqueous sodium hydrogen sulfate,water and brine and were dried with magnesium sulfate. The crude productwas purified by silica column chromatography (ethyl acetate:hexanegradient 1:8-1:4). The desired product 2c was obtained in 79% yield(4.36 g, 8.45 mmol).

MS-ESI: 517 (M⁺ + 1, 100). Elementary C 72.22% H 5.86% F 3.68% N 2.72%analysis: Determined: C 72.20% H 5.87% F 3.67% N 2.71%

d) Synthesis ofN-(5-Fluoro-2-phenoxy-phenyl)-N-(2-hydroxy-5-methoxy-benzyl)-acetamide(2d)

The atmosphere over a stirred solution of 2.58 g (5 mmol)4-fluoro-2-nitro-1-phenoxy-benzene with5-methoxy-2-hydroxy-1-tosyloxy-phenyl and catalytic amount of palladiumon carbon in 35 ml iso-propanol at 20° C. was saturated with hydrogen.The reaction mixture was stirred vigorously at 25° C. for 7 h. Thereaction mixture was filtered over celite. The solvent of the filtratewas evaporated. 10 ml water and 10 ml dichloromethane were added. Theorganic phase was separated. The aqueous phase was extracted three timeswith 10 ml dichloromethane each. The combined organic phases were washedwith 10 ml water and 10 ml brine. The organic phase was dried withmagnesium sulfate and evaporated. The crude product 2d was used withoutpurification. The desired crude product 2d was obtained in 89% yield(1.7 g, 4.45 mmol) as yellow oil.

MS-ESI: 382 (M⁺ + 1, 100). Elementary C 69.28% H 5.29% F 4.98% N 3.67%analysis: Determined: C 69.25% H 5.30% F 4.97% N 3.66%

Example 3 a) Synthesis ofN-(5-Fluoro-2-phenoxyphenyl)-N-[2-(2-mesyloxy-ethoxy)-5-methoxybenzyl]acetamide (3a) corresponding to compound 4c or 13

To a vigorously stirred solution of 38.1 g (100 mmol)N-(5-fluoro-2-phenoxy-phenyl)-N-(2-hydroxy-5-methoxy-benzyl)-acetamide(Biorg. Med. Chem., (2004), 12, 423) and 42.4 g (130 mmol) caesiumcarbonate in 350 ml DMF at 0° C. was added 27.3 g (125 mmol)1,2-bis-methanesulfonyloxy-ethane ((J. Med. Chem.; 47; 17; (2004);4300-4315)) in 50 ml DMF dropwisely. The reaction mixture was stirredvigorously at 70° C. for 6.5 h. The solvent was evaporated. 200 ml waterand 200 ml ethyl acetate were added. The organic phase was separated.The aqueous phase was extracted three times with 100 ml ethyl acetateeach. The combined organic phases were washed with 50 ml water and 50 mlbrine. The organic phase was dried with magnesium sulfate andevaporated. The crude product was purified by silica columnchromatography (gradient ethylacetate:hexane 1:6→1:2). The desiredproduct 3a was obtained in 85% yield (42.8 g, 85 mmol) as yellow oil.

MS-ESI: 505 (M⁺ + 1, 78). Elementary C 59.63% H 5.20% F 3.77% N 2.78%analysis: Determined: C 59.62% H 5.21% F 3.76% N 2.78%

Example 4 a) Synthesis of 5-methoxy-2-(2-mesyloxyethoxy)-benzaldehyd(4a)

To a vigorously stirred solution of 15.2 g (100 mmol)2-hydroxy-5-methoxy-benzaldehyde and 42.4 g (130 mmol) caesium carbonatein 350 ml DMF at 0° C. was added 27.3 g (125 mmol)1,2-bis-methanesulfonyloxy-ethane ((J. Med. Chem.; 47; 17; (2004);4300-4315) in 50 ml DMF dropwisely. The reaction mixture was stirredvigorously at 70° C. for 5 h. The solvent was evaporated. 200 ml waterand 200 ml ethyl acetate were added. The organic phase was separated.The aqueous phase was extracted three times with 100 ml ethyl acetateeach. The combined organic phases were washed with 50 ml water and 50 mlbrine. The organic phase was dried with magnesium sulfate andevaporated. The crude product was purified by silica columnchromatography (gradient ethylacetate:hexane 1:6, ethyl acetate→1:2).The desired product 4a was obtained in 78% yield (21.4 g, 78 mmol) asyellow oil.

MS-ESI: 275 (M⁺ + 1, 100). Elementary analysis: C 48.17% H 5.14%Determined: C 48.19% H 5.15%

b) Synthesis of(5-Fluoro-2-phenoxy-phenyl)-{5-methoxy-2-[2-(mesyloxy-)-ethoxy]-benzyl}-amine(4b)

To stirred solution of 9.1 g (45 mmol) 1b, 12.3 g (45 mmol) 4a and onedrop of glacial acid in 60 ml dichloroethane (pH=5) were added 14.8 g(70 mmol) sodium tris-acetoxy hydro borane. The reaction mixture wasstirred over night and diluted with 5 ml water. The pH value wasadjusted with aqueous sodium hydroxyd solution to pH=8-9. The mixturewas extracted three times with dichloromethane. The combined organicphases were washed with water and brine and were dried with magnesiumsulfate. The desired crude product 4b was obtained in 62% yield (12.9 g,27.9 mmol) as yellow oil. The crude product 4b was used without furtherpurification.

MS-ESI: 463 (M⁺+1, 65).

c)N-(5-Fluoro-2-phenoxy-phenyl)-N-[2-(2-mesyloxy-ethoxy)-5-methoxy-benzyl]-acetamide(4c) corresponding to compound 3a or 13

To a solution of 4.94 g (10.7 mmol) crude 4b in 50 ml ml pyridine wasadded 4.37 g (42.8 mmol) acetic acid anhydride. The reaction mixture wasstirred over night and poured into ice-cold ethyl acetate. The organicphase was washed with water and brine and were dried with magnesiumsulfate. The crude product was purified by silica column chromatography(ethyl acetate:hexane gradient 1:8→1:4). The desired product 4c wasobtained in 80% yield (4.3 g, 8.56 mmol).

MS-ESI: 504 (M⁺ + 1, 78). Elementary C 59.63% H 5.20% F 3.77% N 2.78%analysis: Determined: C 59.61% H 5.19% F 3.79% N 2.77%

Example 5 a) Synthesis of 5-methoxy-2-(2-tosyloxy-ethoxy)-benzaldehyd(5a)

To a vigorously stirred solution of 15.2 g (100 mmol)2-hydroxy-5-methoxy-benzaldehyde and 42.4 g (130 mmol) caesium carbonatein 350 ml DMF at 0° C. was added 46.3 g (125 mmol) ethylene glycolbis-toluene sulfonate (Aldrich) in 50 ml DMF dropwisely. The reactionmixture was stirred vigorously at 70° C. for 5 h. The solvent wasevaporated. 200 ml water and 200 ml ethyl acetate were added. Theorganic phase was separated. The aqueous phase was extracted three timeswith 100 ml ethyl acetate each. The combined organic phases were washedwith 50 ml water and 50 ml brine. The organic phase was dried withmagnesium sulfate and evaporated. The crude product was purified bysilica column chromatography (gradient ethylacetate:hexane 1:6, ethylacetate→1:2). The desired product 5a was obtained in 75% yield (26.3 g,75 mmol) as yellow oil.

MS-ESI: 351 (M⁺ + 1, 100). Elementary analysis: C 58.27% H 5.18%Determined: C 58.27% H 5.17%

b) Synthesis of(5-Fluoro-2-phenoxy-phenyl)-(5-methoxy-2-[2-(tosyloxy-)-ethoxy]-benzyl}-amine(5b)

To stirred solution of 9.1 g (45 mmol) 1b, 15.8 g (45 mmol) 5a and onedrop of glacial acid in 60 ml dichloroethane (pH=5) were added 14.8 g(70 mmol) sodium tris-acetoxy hydro borane. The reaction mixture wasstirred over night and diluted with 5 ml water. The pH value wasadjusted with aqueous sodium hydroxyd solution to pH=8-9. The mixturewas extracted three times with dichloromethane. The combined organicphases were washed with water and brine and were dried with magnesiumsulfate. The desired crude product 5b was obtained in 71% yield (17.2 g,32.0 mmol) as yellow oil. The crude product 5b was used without furtherpurification.

MS-ESI: 539 (M⁺+1, 64).

c) Synthesis ofN-(5-Fluoro-2-phenoxy-phenyl)-N-[2-(2-tosyloxy-ethoxy)-5-methoxy-benzyl]-acetamide(5c)

To a solution of 5.75 g (10.7 mmol) crude 5b in 50 ml pyridine was added4.37 g (42.8 mmol) acetic acid anhydride. The reaction mixture wasstirred over night and poured into ice-cold ethyl acetate. The organicphase was washed with water and brine and were dried with magnesiumsulfate. The crude product was purified by silica column chromatography(ethyl acetate:hexane gradient 1:8→1:4). The desired product 5c wasobtained in 74.5% yield (4.62 g, 7.97 mmol).

MS-ESI: 581 (M⁺ + 1, 100). Elementary C 64.24% H 5.22% F 3.28% N 2.42%analysis: Determined: C 64.22% H 5.23% F 3.26% N 2.41%

Example 6 a) Synthesis ofN-(5-Fluoro-2-phenoxy-phenyl)-N-[2-(2-bromo-ethoxy)-5-methoxy-benzyl]-acetamide(6a)

To a stirred solution of 1.69 g (5.1 mmol) CBr₄ and 2.89 g (11 mmol)PPh₃ in dry dichloromethane (35 mL) 2.04 g (4.8 mmol) (1e) was added at0° C. The reaction mixture was allowed to warm to room temperature andstirred overnight, then diluted with ether and filtered through sinteredfunnel. The filtrate was concentrated and the residue was purified bysilica column chromatography (gradient hexane-ethyl acetate 6:1→2:1).The desired product 6a was obtained in 64% yield (1.37 g, 3.07 mmol).

MS-ESI: 446 (M^(Br79 +) + 1, 100). Elementary C 59.21% H 4.74% F 4.26% N3.14% analysis: Determined: C 59.20% H 4.74% F 4.25% N 3.13%

Example 7 a) Synthesis of 2-(2-hydroxymethyl-4-methoxy-phenoxy)-ethanol

To a stirred solution of 7.7 g (50 mmol)2-hydroxymethyl-4-methoxy-phenol (Rarechem) and 4.0 g (100 mmol) sodiumhydroxyd in 300 ml ethanol and 150 ml water 5.6 g (70 mmol) 2-chloroethanol were added at 0° C. The reaction mixture was stirred vigorouslyover night at 70° C. The reaction mixture was cooled to 0° C. andneutralized by use of 3N HCl to pH=7. The volume of the mixture wasreduced to a fifth of the volume. Dichloromethane was added to theresidue. The mixture was filtered and the filtrate was diluted with 150ml water and 150 ml dichloromethane. The organic phase was separated.The aqueous phase was extracted three times with 200 ml dichloromethane.The combined organic phases were washed with 50 ml water and 50 mlbrine. The organic phase was dried with magnesium sulfate andevaporated. The crude product was purified by silica columnchromatography (gradient hexane:ethyl acetate 1:1→hexane:ethyl acetate:methanol 1:10:0.1). The desired product 7a was obtained in 65% yield(6.44 g; 32.5 mmol).

MS-ESI: 199 (M⁺ + 1, 100). Elementary analysis: C 60.59% H 7.12%Determined: C 64.22% H 5.23%

b) Synthesis of methanesulfonic acid2-(2-methanesulfonyloxy-ethoxy)-5-methoxy-benzyl ester

To a solution of 6.41 g (32.3 mmol) 7a and 13.9 g (106 mmol) diisopropylethyl amine in 25 ml dichloromethane was added 9.7 g (85 mmol) mesylchloride in 5 ml dichloromethane drop wisely at −10° C. The stirredreaction mixture was warmed over a period of 4 h to room temperature anddiluted with dichloromethane. The organic phase was washed withsaturated sodium hydrogen carbonate solution, water and brine. Theorganic phase was dried with magnesium sulfate. The crude product waspurified by silica column chromatography (ethyl acetate:hexane gradient1:4→1:1). The desired product 7b was obtained in 72% yield (8.25 g, 23.3mmol) as yellow oil.

MS-ESI: 355 (M⁺ + 1, 100). Elementary analysis: C 40.67% H 5.12%Determined: C 40.70% H 5.13%

c) Synthesis ofN-(5-fluoro-2-phenoxy-phenyl)-N-[2-(2-mesyloxy-ethoxy)-5-methoxy-benzyl]-acetamide(7c)

To a solution of 1.01 g (5 mmol) 1b and 4.24 g (13.0 mmol) caesiumcarbonate in 50 ml DMF at 0° C. was added 531 mg (1.5 mmol) 7b in 2 mlDMF dropwisely. The reaction mixture was stirred vigorously at 70° C.for 5 h. The solvent was evaporated. 50 ml water and 50 ml ethyl acetatewere added. The organic phase was separated. The aqueous phase wasextracted three times with 50 ml ethyl acetate each. The combinedorganic phases were washed with 10 ml water and 10 ml brine. The organicphase was dried with magnesium sulfate and evaporated. The crude productdiluted in 5 ml pyridine. 2.17 g (21.0 mmol) acetic acid anhydride wereadded. The reaction mixture was stirred over night and poured intoice-cold ethyl acetate. The organic phase was washed with water andbrine and were dried with magnesium sulfate. The crude product waspurified by silica column chromatography (ethyl acetate:hexane gradient1:8→1:4). The desired product 7c was obtained in 72% yield (543 mg, 1.08mmol) as yellow oil.

MS-ESI: 504 (M⁺ + 1, 89). Elementary C 59.63% H 5.20% F 3.77% N 2.78%analysis: Determined: C 59.61% H 5.21% F 3.77% N 2.78%

Example 8 a) Synthesis ofN-(5-Fluoro-2-phenoxyphenyl)-N-(2-(2-[¹⁸F]fluoroethoxy)-5-methoxybenzyl)acetamide(8a) via compound 7

To a Wheaton vial (5 ml) charged with 2.5 mg Kryptofix 222 in 0.75 mlacetonitrile and 0.5 mg potassium carbonate and the fluorine containingwater (2.5 GBq, 250 μl) was added. The solvent was removed by heating at120° C. for 10 mins under a stream of nitrogen. Anhydrous MeCN (1 ml) isadded and evaporated as before. This step is repeated again. A solutionof 7 (2 mg) in 0.705 ml anhydrous DMF is added. After heating at 130° C.for 30 min. The crude reaction mixture is analyzed using an analyticalHPLC: ACE3-C18 50 mm*4.6 mm; solvent: 5% acetonitril—95% acetonitril inwater in 7 min., flow: 2 ml/min. The F-18 labeled product 1g isconfirmed by co-injection with the non-radioactive F-19 fluoro standardon the analytical HPLC. The crude product (221 MBq) was purified bypreparative HPLC column: ACE5-C18-HL 250 mm*10 mm; solvent 62%acetonitril-38% water, isocratic 20 min., flow: 3 ml/min. The desiredproduct 1g was obtained (55 MBq) as reconfirmed by co-injection with thenon-radioactive F-19 fluoro standard on the analytical HPLC.

Example 9 a) Synthesis of5-Methoxy-2-(2-triisopropylsilanyloxy-ethoxy)-phenyl]-methanol

The general procedure A was applied to(2-Bromo-ethoxy)-triisopropyl-silane (J. Med. Chem.; 47; 25; 2004;6124-6127) and 2-hydroxymethyl-4-methoxy-phenol (Aldrich). The desiredcompound 9a was obtained in 87% yield.

MS-ESI: 355 (M⁺ + 1, 100). Elementary analysis: C 64.36% H 9.67%Determined: C 64.38% H 9.68%

b) Synthesis of[2-(2-Bromomethyl-4-methoxy-phenoxy)-ethoxy]-triisopropyl-silane (9b)

The general procedure B was applied to 9a. The desired compound 9b wasobtained in 73% yield (14.6 mmol; 6.07 g).

MS-ESI: 418 (M⁺ + 1, 100). Elementary analysis: C 54.67% H 7.97%Determined: C 54.68% H 7.96%

c) Synthesis ofN-(5-Fluoro-2-phenoxy-phenyl)-N-[5-methoxy-2-(2-triisopropylsilanyloxy-ethoxy)-benzyl]-acetamide(9c)

The general procedure C was applied toN-(5-Fluoro-2-phenoxy-phenyl)-acetamide and 9b. The desired compound 9cwas obtained in 56% yield (3.27 g; 5.61 mmol).

MS-ESI: 583 (M⁺ + 1, 100). Elementary analysis: C 68.13% H 7.62%Determined: C 68.14% H 7.63%

d) Synthesis of 1e from 9c

The general procedure D was applied to 9c. The desired compound 1e wasobtained in 89% yield (2.67 mmol, 1.14 g).

MS-ESI: 426 (M⁺ + 1, 100). Elementary analysis: C 67.75% H 5.69% N 3.29%Determined: C 67.74% H 5.70% N 3.29%

Example 10 a) Synthesis of2-(2-Allyloxy-ethoxy)-5-methoxy-phenyl]-methanol (10a)

The general procedure A was applied to 3-(2-Bromo-ethoxy)-propene (Chem.Soc. Jpn.; 55; 5; 1982; 1498-1503) and 2-hydroxymethyl-4-methoxy-phenol(Aldrich). The desired compound 10a was obtained in 75% yield (22.5mmol; 5.4 g).

MS-ESI: 239 (M⁺ + 1, 100). Elementary analysis: C 65.53% H 7.61%Determined: C 65.54% H 7.60%

b) Synthesis of 1-(2-Allyloxy-ethoxy)-2-bromomethyl-4-methoxy-benzene(10b)

The general procedure B was applied to 10a. The desired compound 10b wasobtained in 67% yield (13.4 mmol; 4.03 g).

MS-ESI: 301/303 (M⁺ + 1, 80). Elementary analysis: C 51.84% H 5.69%Determined: C 51.83% H 5.70%

c) Synthesis ofN-[2-(2-Allyloxy-ethoxy)-5-methoxy-benzyl]-N-(5-fluoro-2-phenoxy-phenyl)-acetamide(10c)

The general procedure C was applied toN-(5-Fluoro-2-phenoxy-phenyl)-acetamide and 10b The desired product 10cwas obtained in 49% yield (4.9 mmol; 2.28 g).

MS-ESI: 467 (M⁺ + 1, 80). Elementary analysis: C 69.66% H 6.06%Determined: C 69.64% H 6.07%

d) Synthesis of 1e from 10c (10d)

According to slightly modified protocol from Syn. Lett. (2003),1061-1063 a solution of 2 mmol (932 mg) 10c and 4 mmol N,N-dimethylbarbituric acid in 10 ml tetrahydrofuran was added 0.04 mmoltetrakis(triphenylphosphin)palladium. The reaction mixture was refluxedover night. Diethyl ether and saturated sodium hydrogen carbonatesolution was added at 0° C. The two-phase mixture was stirred vigorouslyfor 20 min. The organic phase was separated. The aqueous phase wasextracted three times with ethyl acetate. The combined organic phaseswere washed with brine, dried with magnesium sulphate and wereevaporated. The residue was purified by silica chromatography usingethyl acetate/hexane solvent mixtures as gradient. The desired compound1e was obtained in 84% yield (710 mg, 1.68 mmol).

MS-ESI: 426 (M⁺ + 1, 100). Elementary analysis: C 67.75% H 5.69% N 3.29%Determined: C 67.72% H 5.71% N 3.28%

e) Synthesis of Trifluoro-methanesulfonic acid2-(2-{[acetyl-(5-fluoro-2-phenoxy-phenyl)amino]-methyl}-4-methoxy-phenoxy)-ethylester (10e)

To a solution of 426 mg (1 mmol) and 400 mg (5 mmol) pyridine in 6 mldry dichloromethane was added dropwisely 423 mg (1.5 mmol)trifluorosulphonic acid anhydride at −10° C. The reaction mixture wasstirred for 6 h and poured onto a vigorously stirred diethyl ether-watermixture. The organic phase was separated. The aqueous phase wasextracted three times with diethyl ether. The combined organic phaseswere washed with brine, dried with magnesium sulphate and wereevaporated. The residue was purified by silica chromatography usingethyl acetate/hexane solvent mixtures as gradient. The desired compound10e was obtained in 77% yield (430 mg, 0.77 mmol).

MS-ESI: 426 (M⁺ + 1, 100). Elementary analysis: C 53.86% H 4.16% N 2.51%Determined: C 53.88% H 4.17% N 2.51%

1-6. (canceled)
 7. A compound of formula II:

wherein A is a) hydrogen b) SiR¹ ₃ c) CH₂-G d) C(O)-Q e) C(O)O-E f) —(R²-phenyl) g) —((R²)-2-phenyl) h) tetrahydropyranyl i) (1-alkoxy)-alkyl j) (1-alkoxy)-cycloalkyl k) allyl or l) tert-butyl, wherein G is a) phenyl b) alkoxy c) dimethoxyphenyl d) nitrophenyl e) halophenyl f) di-halophenyl g) cyanophenyl h) p-biphenyl i) acylaminophenyl j) triphenyl k) (methoxyphenyl)phenyl l) di(methoxyphenyl)phenyl m) -naphtyldiphenyl, or n) hydrogen and Q is a) hydrogen b) C₁-C₅ branched and unbranched alkyl c) halomethyl d) dihalomethyl e) trihalomethyl f) phenyl g) biphenyl h) triphenylmethoxymethyl and or i) phenoxymethyl, and E is a) lower branched and unbranched alkyl b) methoxymethyl c) vinyl d) allyl e) benzyl f) methoxyphenyl g) dimethoxyphenyl or h) nitrophenyl, and wherein R¹ is a) lower branched and unbranched alkyl, b) phenyl, or c) benzyl, and wherein R² is a) methoxy, b) nitro, c) halo, or d) cyano.
 8. The compound according to claim 7, wherein A is a) hydrogen b) SiR¹ ₃ c) CH₂-G d) tetrahydropyranyl e) allyl or f) tert-butyl.
 9. The compound according to claim 8, wherein A is a) hydrogen b) SiR¹ ₃ c) CH₂-G d) tetrahydropyranyl, or e) tert-butyl.
 10. The compound according to claim 7, wherein G is a) phenyl b) methoxy c) p-methoxyphenyl d) p-nitrophenyl e) p-chlorophenyl, or f) triphenyl.
 11. The compound according to claim 9, wherein G is a) phenyl, b) methoxy, or c) p-methoxyphenyl.
 12. The compound according to claim 7, wherein Q is a) hydrogen b) methyl c) phenyl, or d) phenoxymethyl.
 13. The compound according to claim 12, wherein Q is a) methyl, or b) phenyl.
 14. The compound according to claim 7, wherein E is a) methyl b) tert-butyl c) methoxymethyl, or d) phenyl
 15. The compound according to claim 14, wherein E is a) methyl c) tert-butyl, or b) phenyl
 16. The compound according to claim 7, wherein R¹ is a) methyl b) ethyl c) isopropyl d) tert-butyl e) phenyl, or f) benzyl.
 17. The compound according to claim 16, wherein R¹ is a) methyl b) ethyl c) isopropyl d) tert-butyl, or e) phenyl.
 18. The compound according to claim 7, wherein R² is a) methoxy b) nitro, or c) chloro.
 19. The compound according to claim 18, wherein R² a) methoxy, or b) nitro.
 20. The compound according to claim 7, that is


21. A process for preparing a compound of formula I:

wherein R is —OS(O)₂-L and wherein L is a) methyl b) trifluormethyl c) nonafluorobutyl d) C₁-C₆ alkyl-phenyl e) (2,4,6-C₁-C₆tri-alkyl)-phenyl f) nitro-phenyl or g) halo-phenyl or a compound of formula I wherein L is (para-methyl)-phenyl, comprising: a) reductively N-alkylating a compound of formula III:

with an aldehyde of formula IV

and subsequent N-acetylation, or b) N-alkylating an aniline of formula V:

with an electrophile of formula VI

and subsequent N-acetylation, or c) alkylation of phenol 4 with an

electrophile of formula VII

d) N-alkylating of the compound of formula VIII

with an electrophile of formula VI wherein X is a) nitro or b) amino, and Z is, independently, a) R, b) tosyloxy, or c) O-A, and wherein R³ is independently a) R, or b) tosyloxy.
 22. The process according to claim 21, wherein Z is a) methanesulphonyloxy b) trifluoromethansulphonyloxy c) nonafluorobutanesulfonyloxy d) tosyloxy e) bromo, or f) O-A.
 23. The process according to claim 22, wherein Z is a) methanesulphonyloxy b) trifluoromethansulphonyloxy c) nonafluorobutanesulfonyloxy d) tosyloxy e) bromo f) hydroxyl g) (tert-butyl dimethyl)silyloxy h) (triisopropyl)silyloxy ii) phenyl-methyl)oxy jj) (2-tetrahydropyranyl)oxy I, or kk) tert-butyloxy.
 24. The process according to claim 21, wherein R³ is a) R. 25.-29. (canceled)
 30. A kit comprising a sealed vial containing a compound according to claim 7 wherein, said sealed vial contains a predetermined quantity of said compound.
 31. (canceled)
 32. A method diagnostic imaging comprising administering a diagnostically effective amount of a diagnostic imaging agent comprising a compound according to claim
 7. 33. A method according to claim 32, wherein said diagnostic imaging agent is far administered to image diseases of the central nervous system.
 34. A process of preparing compound 3

comprising a) reacting compound 7

with ¹⁸F anions, at temperatures in the range of from 121° C. to 160° C., and, optionally, upon obtainment of compound 3, adding acid.
 35. The process of preparing compound 3

comprising reacting a compound of formula I,

wherein R is —OS(O)₂-L and wherein L is a) methyl b) trifluormethyl c) nonafluorobutyl d) C₁-C₆ alkyl-phenyl e) (2,4,6-C₁-C₆ tri-alkyl)-phenyl f) nitro-phenyl or g) halo-phenyl with the proviso that L is not (para-methyl)-phenyl. with ¹⁸F anions at temperatures in the range of from 75° C. to 150° C.
 36. The process according to claim 35, wherein said temperatures are in the range of from 85° C. to 140° C.
 37. The process according to claim 34, comprising reacting compound 7 with ¹⁸F anions at temperatures in the range of from 121° C. to 150° C., and, optionally, upon obtainment of compound 3, adding at least one mineral acid having a concentration in the range of from 0.5N-6N.
 38. The process according to claim 34, comprising reacting compound 7 with ¹⁸F anions, at temperatures in the range of from 121° C. to 140° C., and, optionally upon obtainment of compound 3, adding at least one mineral acid having a concentration in the range of from 2N-6N. 